In order to overcome the defects in chemical analysis on determining the content of polyer bonded explosive(PBX),such as low testing rate,inefficiency,highcost and so on,the composition contents of PBX booster explosive were analyzed by UV/Visible spectrophotometric method. The condition of color reaction of HMX was studied and selected in visible spectrum. The measuring wavelength (λ=550 nm) was also determined,and the absorbance of HMX solution with concentration of 0.0018 mg·mL^-1 was given at this wavelength,and the recovery was determined to be 98.9%-101.0%. The HMX content in PBX booster was calculated based on this method,and the analysis result (95.47%) was slightly higher than that of chemical analysis (94.99%).